All subjects will be clinically evaluated at IND by a two movement disorders experts. At the baseline visit all subjects will also undergo [123I]ß-CIT SPECT ANAM, voice acoustics, olfactory, Spiral and biochemical testing. Each movement disorders expert will make an initial clinical diagnosis at baseline and again within three months follow-up. At the three month visit one movement disorder expert will be provided the DAT imaging data and will review that data with the subjects and referral physician. The other movement disorders physician will remain blind to the imaging and all other biomarker data. The blinded movement disorders expert will provide a final clinical diagnosis at the 12 month follow-up visit, which will represent the 'gold standard' diagnosis in this study. Statistical analysis to determine the sensitivity and specificity of ANAM, voice acoustics, olfactory, Spiral and biochemical testing compared to [123I]ß-CIT SPECT, and the gold standard clinical diagnosis will be completed. All subjects with DAT deficit and 10% of those without DAT deficit will be asked to return for repeat evaluation at 24 months.